Solar Energy in 3D

March 29th, 2012by Sara Pernas

A group of researchers at the Massachusetts Institute of Technology (MIT) have developed a new structure consisting in cubes or towers that extend solar cells upward in 3D configurations. Once tested, the researchers discovered that the solar cells in these new structures output more than twenty times the power they produce in a fix roof, even in cloudy days.

The biggest boosts in power were seen in the situations where improvements are most needed: 3D structures, the team reports, can gather slanting sunlight better than can flat panels in locations far from the equator, in winter months and on cloudier days. The new findings, based on both computer modeling and outdoor testing of real modules, have been published in the journal Energy and Environmental Science.

Although placing solar cells in these new 3D structures is much more expensive that doing it in a common flat solar panel, it’s expected that the extra power produced will balance the initial inversion.

For an accordion-like tower – the tallest structure the team tested – the idea was to simulate a tower that “you could ship flat, and then could unfold at the site,” says Jeffrey Grossman, Carl Richard Soderberg Career Development Associate Professor of Power Engineering at MIT. Such a tower could be installed in a parking lot to provide a charging station for electric vehicles, he says.

On the other hand, the team has also built individual 3-D modules, to study the shadows that one tower would cast on others at different times of day. In general, 3-D shapes could have a big advantage in any location where space is limited, they say. Such shapes could also be used in larger-scale applications, such as solar farms, once shading effects between towers are carefully minimized.

David Gracias, an associate professor of chemical and biomolecular engineering at Johns Hopkins University who was not involved in this research, says that Grossman and his team “have demonstrated theoretical and proof-of-concept evidence that 3-D photovoltaic elements could provide significant benefits in terms of capturing light at different angles. The challenge, however, is to mass produce these elements in a cost-effective manner.”